The present invention concerns a method and apparatus to facilitate the repair of warp threads in weaving looms using a system for manipulating fallen drop wires.
Drop wires are conventionally used in warp detector systems. Each warp thread is threaded through a warp detector wire such that, in the event of a break in a warp thread, the corresponding wire drops vertically, whereupon the event is detected in an appropriate manner and the loom is stopped.
Taking into account the large density of the warp threads, i.e. 40 to 60 threads per cm., it is quite obvious that a very tight and compact drop wire system is required. The drop wires are thus always mounted in rows (hereinafter "packs"), wherein the wires of the same row come into contact with a common electrode when the wires drop to provide a signal that a warp thread has broken. As this wire package is very compact, it is obviously quite difficult for the weaver to determine a position of the broken warp thread and to carry out the repair of the broken warp. An improvement aimed at facilitating the repair of a broken weft is described in U.S. patent application Ser. No. 014,778 filed Feb. 13, 1987 and commonly owned with this application. The aforesaid patent application describes a method whereby the fallen drop wire is caught by a gripper and moved above the wire pack in such a way that the weaver can easily carry out a repair. In order to achieve direct accessability with the hands to the wire involved, the adjacent drop wires are pushed laterally apart from each other by means of rotatable arms.
Although such a device provides a noticeable improvement over known warp detector systems, it has, however, the disadvantage that, owing to the position of the presented wire, it is quite difficult to carry out an automatic re-threading.
The present invention concerns a different method whereby the aforesaid disadvantage is overcome and whereby automatic re-threading of the wire is facilitated. This does not preclude, of course, manual repair of the warp thread.